Battery management system and power consumption equalization method

Abstract

The invention discloses a power consumption balancing method and a battery management system applying the same, and the method comprises the steps: converting the relation between the power consumption and the magnitude of current which needs to be measured originally into the relation between the power consumption and a voltage signal and time information which can be directly read by an MCU, and calculating a calculation signal representing the input current of each battery monitoring wafer according to the relation; and respectively compensating the input current of each battery monitoring wafer according to the plurality of calculation signals until all the calculation signals are approximately consistent. Therefore, the power consumption equalization among a plurality of battery monitoring wafers can be realized on line by the MCU without depending on a current measurement result, and the real-time performance and the flexibility of the power consumption equalization are improved.

Description

Technical Field

[0001] The present invention relates to the technical field of battery management, and more particularly, to a power consumption balancing method and a battery management system applying the same. Background Art

[0002] As a major pillar behind intelligent driving, the BMS (Battery Management System) protects the safe use of the power batteries of electric vehicles. The BMS is a system for monitoring and managing batteries. By calculating the parameters such as the voltage, current, temperature, and SOC (state of charge) of each battery pack, the charging and discharging process of the battery is controlled, thereby realizing the protection of the battery and improving the management system of the comprehensive performance of the battery.

[0003] In a high-voltage BMS system, keeping the charge states of the individual batteries in the battery pack relatively consistent is beneficial to extending the battery life, improving the charging and discharging efficiency, and safety. The control module of the BMS system includes multiple AFEs (Analog Front End battery monitoring wafers) and a control unit MCU. Since each AFE obtains the supply voltage from the battery pack it monitors, balancing the power consumption between different AFEs is beneficial to the charge balance between battery packs. The reason is that under normal operating conditions, the individual batteries are connected in series, and only in the normal power consumption mode, the charges are basically balanced during the high-voltage charging and discharging processes of all individual batteries; however, in addition to the normal high-voltage charging and discharging, the battery pack also supplies power to the battery monitoring wafer AFE, which is equivalent to its load. If the power consumption of the AFE is not balanced, it will cause the battery charge to be unbalanced when converted to the battery.

[0004] The power consumption differences between different AFEs mainly come from two aspects. One is that the communication positions of the AFEs in the system are different, resulting in differences in communication power consumption; the other is that the number of battery strings monitored by different AFEs may be different, resulting in differences in static power consumption. In addition, the differences between different chips in the design and manufacturing process of the AFE chip will also bring a certain power consumption difference.

[0005] For the problem of uneven AFE power consumption, the existing solutions mainly include: 1) adopting a ring-shaped daisy-chain communication architecture to compensate for the communication power consumption difference by switching the communication direction; 2) adding a dedicated current source inside the AFE for power consumption compensation. This solution requires using a current measurement element or device to actually measure the power consumption difference, and then configuring the compensation value of the current source through a register.

[0006] However, Solution 1 requires switching the communication direction, which involves re-addressing and reconfiguring registers, and the control is relatively complex. For Solution 2, whether it is determining the compensation value for power consumption balance or judging the effect after compensation, it depends on the actual measurement results of the power consumption current. Since the power consumption current of the AFE is very small, additional devices or components are required during measurement, which not only increases the cost and workload, but also makes the solution lack flexibility, and the MCU cannot achieve power consumption balance between AFEs online. Summary of the Invention

[0007] In view of this, the present invention provides a power consumption balancing method and a battery management system applying the same, in order to achieve online power consumption balance among multiple battery monitoring wafers by a control unit MCU without relying on the current measurement results.

[0008] In a first aspect, the present invention provides a battery management system, characterized by comprising:

[0009] Multiple battery monitoring wafers, configured to respectively monitor the status information of corresponding multiple battery packs in a battery module, and

[0010] A control unit, configured to generate a calculation signal representing the input current at the input end of each of the battery monitoring wafers, and the calculation signal is determined by the topology of the DC-DC converter in each battery detection wafer;

[0011] Wherein, each of the battery monitoring wafers includes a DC-DC converter and a current compensation module. The DC-DC converter is configured to receive the battery pack voltage at the input end of the battery monitoring wafer and convert it into a power supply voltage for powering the battery monitoring wafer; the current compensation module is configured to generate a compensation current according to the calculation signal to compensate the input current, so that the calculation signals of the multiple battery monitoring wafers corresponding to the multiple battery packs tend to be consistent.

[0012] Preferably, the control unit respectively reads the voltage information and time information of each of the battery monitoring wafers; and respectively obtains the corresponding calculation signals according to the voltage information and time information of each of the battery monitoring wafers.

[0013] Preferably, the maximum value among all the calculation signals is used as the reference value of the input current, and the compensation current is generated according to the difference between each calculation signal and the reference value of the input current.

[0014] Preferably, the current compensation module is a current source built in the battery monitoring wafer, and the current source is used to output the compensation current.

[0015] Preferably, different step sizes are respectively selected according to the difference between each of the calculated signals and the reference value of the input current to adjust the corresponding current source to output the corresponding compensation current, wherein the value of the step size is positively correlated with the value of the corresponding difference.

[0016] Preferably, at least some components of the DC-DC converter are built into the battery monitoring chip.

[0017] Preferably, the voltage information is the input voltage and the output voltage of the DC-DC converter, and the time information is the switching period of the main power switch of the DC-DC converter and the conduction time within each switching period.

[0018] Preferably, the DC-DC converter is a Buck converter and operates in the DCM mode.

[0019] Preferably, the calculated signal is directly proportional to the square of the conduction time of the main power switch within each switching period and the difference between the input voltage and the output voltage of the DC-DC converter, and is inversely proportional to the switching period of the main power switch.

[0020] Preferably, the DC-DC converter is a Buck-Boost converter and operates in the DCM mode.

[0021] Preferably, the calculated signal is directly proportional to the square of the conduction time of the main power switch within each switching period and the input voltage of the DC-DC converter, and is inversely proportional to the switching period of the main power switch.

[0022] Preferably, the control unit communicates with the multiple battery monitoring chips through a daisy chain to read the voltage information and time information of each battery monitoring chip and generate multiple calculated signals accordingly, and compensates the input current of each battery monitoring chip according to the multiple calculated signals until all the calculated signals are close to being consistent.

[0023] In a second aspect, the present invention provides a power consumption balancing method for balancing the power consumption among multiple battery monitoring chips, where each battery monitoring chip is used to monitor the state information of a corresponding battery pack, and the method includes:

[0024] Generating a calculated signal representing the input current at the input end of the monitoring chip, where the calculated signal is determined by the topology of the DC-DC converter, and the DC-DC converter is used to receive the battery pack voltage at the input end of the monitoring chip and convert it into a power supply voltage for powering the monitoring chip;

[0025] Compensation currents are generated based on each of the calculated signals to compensate the input currents of each battery monitoring wafer respectively, so that the calculated signals of multiple battery monitoring wafers tend to be consistent.

[0026] Preferably, the compensation current is superimposed on the input current to compensate the input current.

[0027] Preferably, the maximum value in the calculated signals is used as the reference value of the input current, and the compensation current is generated according to the difference between each calculated signal and the reference value of the input current.

[0028] Preferably, the compensation current is output by a current source built in the battery monitoring wafer.

[0029] Preferably, according to the magnitude of the difference between each calculated signal and the reference value of the input current, different step sizes are respectively selected to adjust the corresponding current source to output the corresponding compensation current, wherein the value of the step size is positively correlated with the value of the corresponding difference.

[0030] Preferably, at least some components of the DC-DC converter are built in the battery monitoring wafer.

[0031] Preferably, power consumption balance among multiple battery monitoring wafers is achieved by equalizing the input current of the DC-DC.

[0032] Preferably, the voltage information is the input voltage and output voltage of the DC-DC converter, and the time information is the switching period of the main power switch of the DC-DC converter and the conduction time within each switching period.

[0033] Preferably, the DC-DC converter is a Buck converter and operates in the DCM mode.

[0034] Preferably, the calculated signal is directly proportional to the square of the conduction time of the main power switch within each switching period and the difference between the input voltage and output voltage of the DC-DC converter, and inversely proportional to the switching period of the main power switch.

[0035] Preferably, the DC-DC converter is a Buck-Boost converter and operates in the DCM mode.

[0036] Preferably, the calculated signal is directly proportional to the square of the conduction time of the main power switch within each switching period and the input voltage of the DC-DC converter, and inversely proportional to the switching period of the main power switch.

[0037] Preferably, the control unit communicates with the multiple battery monitoring wafers through a daisy chain to read the voltage information and time information of each battery monitoring wafer and generate multiple calculation signals accordingly, and compensates the input current of each battery monitoring wafer according to the multiple calculation signals until all the calculation signals are close to being consistent.

[0038] The present invention discloses a power consumption balancing method and a battery management system applying the same. By converting the relationship between power consumption and the current amount that originally needed to be measured into the relationship between power consumption and the voltage signal and time information that can be directly read by the MCU, and calculating the calculation signals representing the input current of each battery monitoring wafer according to this relationship, and then compensating the input current of each battery monitoring wafer according to the multiple calculation signals until all the calculation signals are close to being consistent. Thus, the MCU can achieve power consumption balance between multiple battery monitoring wafers online without relying on the current measurement results, improving the real-time performance and flexibility of power consumption balancing. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the drawings in the following description are only the embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained according to the provided drawings without creative efforts.

[0040] Figure 1 is a schematic diagram of the battery management system according to the embodiment of the present invention;

[0041] Figure 2 is a schematic diagram of a partial structure of a battery monitoring wafer according to the embodiment of the present invention;

[0042] Figure 3 is a schematic diagram of a partial structure of another battery monitoring wafer according to the embodiment of the present invention;

[0043] Figure 4 is a flowchart of the power consumption balancing method of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0044] The following describes the present invention based on embodiments, but the present invention is not limited to these embodiments. In the following detailed description of the present invention, some specific details are described in detail. Those skilled in the art can fully understand the present invention without the description of these details. In order to avoid obscuring the essence of the present invention, well-known methods, processes, procedures, elements, and circuits are not described in detail.

[0045] In addition, those of ordinary skill in the art should understand that the accompanying drawings provided herein are for illustrative purposes only and are not necessarily drawn to scale.

[0046] Meanwhile, it should be understood that in the following description, a "circuit" refers to a conductive loop formed by at least one component or sub-circuit through electrical connection or electromagnetic connection. When an element or circuit is said to be "connected to" another element or when an element / circuit is said to be "connected between" two nodes, it can be directly coupled or connected to another element or there may be intermediate elements. The connection between elements can be physical, logical, or a combination thereof. In contrast, when an element is said to be "directly coupled to" or "directly connected to" another element, it means there are no intermediate elements between the two.

[0047] Unless the context clearly requires otherwise, the words such as "including", "comprising" and the like in the whole specification and claims should be interpreted in an inclusive sense rather than an exclusive or exhaustive sense; that is, it is the meaning of "including but not limited to".

[0048] In the description of the present invention, it should be understood that the terms "first", "second", etc. are only used for descriptive purposes and cannot be construed as indicating or implying relative importance. In addition, in the description of the present invention, unless otherwise specified, the meaning of "a plurality of" is two or more.

[0049] Figure 1 It is a schematic diagram of the battery management system according to the first embodiment of the present invention. As Figure 1 shown, the battery management system is used to manage a plurality of serially coupled battery packs. The battery management system includes: M battery monitoring chips AFE1 to AFEM, which are respectively used to collect information such as the voltage or temperature of the corresponding battery pack; and a control unit MCU, which is used to control the plurality of battery monitoring chips; wherein, each battery pack has at least one battery cell, M is a positive integer, and M≥2.

[0050] The control unit MCU is used to generate a calculation signal representing the input current at the input end of each of the battery monitoring chips, and the calculation signal is determined by the topology of the DC-DC converter; each battery monitoring chip includes a DC-DC converter and a current compensation module. The DC-DC converter is used to receive the battery pack voltage at the input end of the battery monitoring chip and convert it into a power supply voltage for powering the battery monitoring chip; the current compensation module is used to generate a compensation current and superimpose the compensation current on the input current to compensate the input current, so that the calculation signals of the plurality of battery monitoring chips corresponding to the plurality of battery packs tend to be consistent.

[0051] Specifically, the control unit MCU reads the voltage information and time information of each battery monitoring chip respectively; and obtains the corresponding calculation signal according to the voltage information and time information of each battery monitoring chip. In a preferred embodiment, the control unit MCU uses the maximum value of all calculation signals as the reference value of the input current, and generates the corresponding compensation current according to the difference between each calculation signal and the reference value of the input current.

[0052] Preferably, the current compensation module is a current source built into the battery monitoring chip, and the current source is used to output the compensation current. In one embodiment, the compensation current is superimposed on the input current of the DC-DC converter to compensate for the input current; in another embodiment, the compensation current is superimposed on the output current of the DC-DC converter to compensate for the input current. It can be understood that when the compensation current is superimposed on the output current of the DC-DC converter, it is necessary to convert it according to the numerical relationship between the input current and the output current of the DC-DC converter, and superimpose the converted compensation current on the output current of the DC-DC converter. The control unit MCU selects different step sizes to adjust the corresponding current source according to the value of the difference between each calculated signal and the reference value of the input current to output the corresponding compensation current, wherein the value of the step size is positively correlated with the value of the corresponding difference.

[0053] In one embodiment, the number of battery strings x in each battery pack is equal, that is, each battery monitoring chip monitors the same number of battery cells; in another embodiment, the number of battery strings x in each battery pack is unequal, that is, each battery monitoring chip monitors a different number of battery cells. The present invention is not limited to this, and the power consumption balancing method executed in the battery management system of the present invention can also balance the power consumption difference between battery monitoring chips caused by the different number of battery strings in the battery pack.

[0054] Preferably, the control unit MCU includes a transceiver ( Figure 1 The MCU and each battery monitoring chip adopt a daisy chain communication architecture, and the transceiver is responsible for sending read and write commands to the M battery monitoring chips AFE1-AFEM and receiving feedback information. It should be noted that the present invention is not limited to this. For example, in another preferred embodiment, each battery monitoring chip and the MCU can also communicate in an isolated manner.

[0055] The power consumption balancing method executed by the battery management system of the embodiment of the present invention is used to balance the power consumption among multiple battery monitoring chips, each battery monitoring chip is used to monitor the status information of a corresponding battery group, and multiple battery groups are connected in series and parallel to form a battery module.

[0056] As shown Figure 2 in the figure, it is a schematic diagram of a partial structure of the battery monitoring wafer according to an embodiment of the present invention. In the embodiment of the present invention, the battery monitoring wafer 20 includes a DC-DC converter and a current compensation module 21. The DC-DC converter is used to receive the battery pack voltage at the input pin BAT of the battery monitoring wafer and convert it into a supply voltage Vout for powering the battery monitoring wafer 20. The current compensation module 21 is used to generate a compensation current I1 and superimpose the generated compensation current I1 on the input current to compensate the input current, so that the calculation signals of multiple battery monitoring wafers corresponding to multiple battery packs tend to be consistent.

[0057] In a preferred embodiment, the DC-DC converter is configured as a Buck converter and operates in the DCM mode. The input end of each Buck converter is coupled to the input pin BAT of each battery monitoring wafer. The power switch Q is coupled between the SW pin and the BAT pin and is built into the battery monitoring wafer. Preferably, the inductor L and the diode D are arranged on the periphery of the battery monitoring wafer, and the common node of the inductor L and the diode D is coupled to the SW pin. The supply voltage Vout is output at the common node of the inductor L and the output capacitor C. The supply voltage vout provides low-voltage power supply for the battery monitoring wafer through the power supply pin VREG of the battery monitoring wafer. Based on this power supply scheme with a built-in DC-DC converter, the power consumption balancing method proposed by the present invention can achieve online power consumption balancing between the battery monitoring wafers AFE1 to AFEM by the control unit MCU without relying on the current measurement results.

[0058] Based on the battery monitoring wafer 20 with a built-in Buck converter, the expression for power consumption balancing of the battery monitoring wafer 20 is derived below. According to the following derivation formula, the present invention aims to convert the relationship between power consumption and the current amount that needs to be measured originally into the relationship between power consumption and the voltage signal and time information that the MCU can directly read.

[0059] Assume that in different operating modes of the battery monitoring wafer 20, the Buck converter is designed to operate in the DCM mode. Therefore, the expression for its duty cycle D can be obtained:

[0060]

[0061] where L represents the inductance value of the inductor, Vin represents the voltage of the input pin BAT of the battery monitoring wafer 20, Vout represents the voltage of the power supply pin VREG, Iout represents the output current, Tsw represents the switching period of the Buck converter, and η represents the operating efficiency of the Buck converter. Equivalent transformation of the above formula can obtain:

[0062]

[0063] Among them, Iin represents the input current of the input pin BAT. Further equivalent transformation gives:

[0064]

[0065] For any two battery monitoring chips AFE n and AFE p, where n and p are any two positive integers between 2 and M (including 2 and M), the difference in their input currents can be expressed as:

[0066]

[0067] Assuming that different battery monitoring chips have the same inductance L, output voltage Vout, and efficiency η, then we can get:

[0068]

[0069] Among them, Ton represents the duration of the high level within a switching period Tsw of the Buck converter, that is, the conduction time of the main power switch within a switching period Tsw. When the power consumption of two battery monitoring chips AFE is balanced, that is, ΔIin → 0, we can get:

[0070]

[0071] Use Vcal(i) to represent the above calculation signal characterizing the input current Iin We can get:

[0072] Vcal(n) - Vcal(p) → 0

[0073] In the expression of the above calculation signal Vcal(i), the input voltage Vini can be measured and obtained through the voltage ADC in the corresponding battery monitoring chip 20, the conduction time Toni and the switching period Tswi can also be measured and obtained by the battery monitoring chip under the system clock, and the supply voltage vout is a known quantity. Therefore, the embodiment of the present invention can transform the relationship between the power consumption (the input current of the AFE) and the current quantity that originally needed to be measured into the relationship between the power consumption and the voltage signal and time information that the MCU can directly read.

[0074] It should be noted that, since the power consumption of the battery is P = V * I, that is, the product of the current and the voltage. Assuming that the voltages of all single cells are the same, then what affects the battery power consumption is the current flowing in and out of the battery. When the input current Iin of all battery monitoring chips AFE is the same, the power consumption of all batteries will be the same; when the input current Iin of one or several battery monitoring chips AFE becomes larger, the power consumption of all batteries corresponding to the corresponding battery monitoring chip AFE will become larger. After working for a period of time, the battery voltages corresponding to the battery monitoring chips AFE with larger input current Iin will be lower than those of other batteries. Further, in the embodiments of the present invention, it can be considered that the input current of the battery monitoring chip AFE is the current flowing in from the input pin BAT, that is, the input current of the DC-DC converter. Therefore, the present invention can adjust the input current of the DC-DC converter to make the input currents of all battery monitoring chips AFE the same, so as to achieve charge balance between different battery packs by controlling the power consumption balance between different battery monitoring chips AFE.

[0075] In the embodiments of the present invention, the power consumption of the battery monitoring chip AFE is directly related to the voltage signal and time information that can be directly read by the MCU. The voltage information is the input voltage Vin and output voltage Vout of the corresponding DC-DC converter, and the time information is the switching period Tsw of the main power switch of the DC-DC converter and the conduction time Ton within each switching period Tsw. Further, the calculation signal Vcal representing the input current Iin of the battery monitoring chip AFE is in direct proportion to the square of the conduction time Ton of the main power switch within each switching period Tsw and the difference between the input voltage Vin and output voltage Vout of the DC-DC converter, and is in inverse proportion to the switching period Tsw of the main power switch.

[0076] It should also be noted that the DC-DC converter in the embodiments of the present invention is not limited to the Buck converter, and the working mode of the DC-DC converter is not limited to DCM. For different DC-DC converter topologies and corresponding working modes, different relationships between power consumption and voltage signals and time information can be deduced, and the present invention does not make any limitations in this regard.

[0077] Such as Figure 3As shown, in another preferred embodiment, different from the first embodiment: the DC-DC converter is configured as a Buck-Boost converter and operates in the DCM mode. Similarly, the input terminal of the Buck-Boost converter is coupled to the input pin BAT of the battery monitoring chip 30, the power switch is coupled to the SW pin and is built into the battery monitoring chip AFE. Preferably, the inductor L and the diode D are arranged on the periphery of the battery monitoring chip AFE, and the common node of the inductor L and the diode D is coupled to the SW pin. The supply voltage Vout is output at the common node VREG of the diode D and the output capacitor C, and this supply voltage vout provides low-voltage power supply for the battery monitoring chip AFE through the power supply pin VREG of the battery monitoring chip AFE. Based on this power supply scheme with a built-in DC-DC converter, the power consumption balancing method proposed by the present invention can achieve power consumption balancing between the battery monitoring chips AFE1 to AFEM online by the MCU without relying on the current measurement results.

[0078] Based on the battery monitoring chip 30 with a built-in Buck-Boost converter, the following is the derivation of the expression for power consumption balancing of the battery monitoring chip 30. According to the following derivation formula, the present invention aims to transform the relationship between power consumption and the current that originally needed to be measured into the relationship between power consumption and the voltage signal and time information that the MCU can directly read.

[0079] Assume that in different operating modes of the battery monitoring chip 30, the Buck-Boost converter is designed to operate in the DCM mode. Therefore, the expression for its duty cycle D can be obtained:

[0080]

[0081] Where, L represents the inductance value of the inductor, Vin represents the voltage of the input pin BAT of the battery monitoring chip 30, Vout represents the voltage of the power supply pin VREG, Iout represents the output current, Tsw represents the switching period of the Buck-Boost converter, and η represents the operating efficiency of the Buck converter. By performing equivalent transformation on the above formula, we can get:

[0082]

[0083] Where, Iin represents the input current of the input pin BAT. Further equivalent transformation gives:

[0084]

[0085] For any two battery monitoring chips AFEn and AFEp, here, n and p are any two positive integers between 2 and M (including 2 and M), and the difference in their input currents can be expressed as:

[0086]

[0087] Assume that different battery monitoring chip AFE has the same inductance L, output voltage Vout, and efficiency η, then we can get:

[0088]

[0089] Where Ton represents the duration of the high level within a switching period Tsw of the Buck - Boost converter, that is, the conduction time of the main power switch within a switching period Tsw. When the power consumption of two battery monitoring chip AFEs achieves balance, i.e., ΔIin → 0, we can get:

[0090]

[0091] Use Vcal(i) to represent the above - mentioned calculated signal characterizing the input current Iin We can get:

[0092] Vcal(n) - Vcal(p) → 0

[0093] In the embodiment of the present invention, the power consumption of the battery monitoring chip AFE is directly related to the voltage signal and time information that can be directly read by the MCU. And the voltage information is the input voltage Vin of the DC - DC converter, and the time information is the switching period Tsw of the main power switch of the DC - DC converter and the conduction time Ton within each switching period Tsw. Further, the calculated signal Vcal characterizing the input current Iin of the battery monitoring chip AFE is in direct proportion to the square of the conduction time Ton of the main power switch within each switching period Tsw and the input voltage Vin of the DC - DC converter, and in inverse proportion to the switching period Tsw of the main power switch.

[0094] Preferably, when the battery management system of the embodiment of the present invention executes the power consumption balancing method, the MCU communicates with M battery monitoring chips AFE1 - AFEM through a daisy chain to read the voltage information and time information of each battery monitoring chip AFE and generate multiple corresponding calculated signals Vcal characterizing the input current Iin of the battery monitoring chip AFE, and compensates the input current Iin of each battery monitoring chip AFE according to the multiple calculated signals Vcal until all the calculated signals Vcal are close to being consistent.

[0095] Specifically, when compensating the input current Iin of each battery monitoring chip AFE, within each monitoring period, the maximum value among all the calculation signals Vcal is used as the reference value Iref of the input current Iin, and the corresponding input current Iin is compensated according to the difference between each calculation signal Vcal and the reference value Iref of the input current Iin. After adjustment through several monitoring periods, finally, the calculation signals Vcal of the input currents Iin of all the battery monitoring chips AFE are made to be close to each other, so as to make the input currents Iin of all the battery monitoring chips AFE tend to be the same, which is conducive to the balance of the power consumption of the M battery monitoring chips.

[0096] Further, a current source is provided in each battery monitoring chip AFE. In a preferred embodiment, the output terminal of the current source is coupled to the output terminal (i.e., the VREG pin) of the DC-DC converter to compensate the input current Iin with the current of the current source; in another embodiment, the output terminal of the current source is coupled to the input terminal (i.e., the BAT pin) of the DC-DC converter to compensate the input current Iin with the current of the current source. It can be understood that if the DC-DC is a buck converter, that is, its output terminal is the low-voltage side, setting the current source on the low-voltage side is beneficial to cost reduction.

[0097] The MCU reads the time information and voltage information of each battery monitoring chip AFE through the daisy chain within each monitoring period, and calculates the calculation signal Vcal of the input current Iin of each battery monitoring chip AFE accordingly. According to the difference between each calculation signal Vcal and the reference value Iref of the input current Iin, the magnitude of the current output by the current source in the corresponding battery monitoring chip AFE is adjusted respectively to compensate its input current Iin.

[0098] Furthermore, the MCU transmits the difference between each calculation signal Vcal and the reference value Iref of the input current Iin to each battery monitoring chip AFE through the daisy chain, and according to the magnitude of the difference between each calculation signal Vcal and the reference value Iref of the input current Iin, different step sizes are correspondingly selected to adjust the corresponding current source to compensate the input current lin of the corresponding battery monitoring chip AFE. In a preferred embodiment, the step size of the adjustment of the current source can be positively correlated with the difference. When the difference is larger, a larger step size can be selected to adjust the magnitude of the current of the current source; when the difference is smaller, a larger step size can be selected to adjust the magnitude of the current of the current source, in order to adjust the input currents Iin of all the battery monitoring chips AFE to be close to each other within the shortest time.

[0099] As can be seen so far, in the power consumption balancing method of the present invention, the relationship between power consumption and the current value that originally needed to be measured is transformed into the relationship between power consumption and the voltage signal and time information that can be directly read by the MCU. Based on this relationship, a calculation signal representing the input current of each battery monitoring chip is calculated. Then, based on multiple calculation signals, the input current of each battery monitoring chip is compensated respectively until all the calculation signals are close to being consistent. Thus, the MCU can achieve power consumption balance among multiple battery monitoring chips online without relying on the current measurement results, improving the real-time performance and flexibility of power consumption balancing.

[0100] Figure 4 The flowchart of the power consumption balancing method of the present invention is shown. The power consumption balancing method includes the following steps:

[0101] S1: Read the voltage information and time information of each of the battery monitoring chips respectively;

[0102] S2: Obtain calculation signals representing the input current of each of the battery monitoring chips respectively according to the voltage information and time information of each of the battery monitoring chips;

[0103] S3: Compensate the input current of each battery monitoring chip respectively according to each of the calculation signals to achieve power consumption balance among the multiple battery monitoring chips: Among them, it further includes:

[0104] S31: Use the maximum value among the calculation signals as the reference value of the input current;

[0105] S32: Calculate the difference between each calculation signal and the reference value of the input current;

[0106] S33: Adjust the corresponding current source according to each difference to compensate the input current of the corresponding battery monitoring chip;

[0107] S4: Determine whether all the calculation signals tend to be consistent. If so, end; if not, repeat the operation of S1.

[0108] The above are only the preferred embodiments of the present invention and are not used to limit the present invention. For those skilled in the art, various modifications and changes can be made to the present invention. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A battery management system, characterized in that: include: A plurality of battery monitoring chips, used to respectively monitor the status information of the corresponding plurality of battery packs in the battery module, and A control unit for generating a calculation signal representing an input current at an input end of each of the battery monitoring chips, wherein the calculation signal is determined by a topology of a DC-DC converter in each of the battery detection chips; Each of the battery monitoring chips includes a DC-DC converter and a current compensation module, wherein the DC-DC converter is used to receive the battery pack voltage at the input end of the battery monitoring chip and convert it into a power supply voltage for powering the battery monitoring chip; The current compensation module is used to generate a compensation current according to the calculation signal to compensate the input current, so that the calculation signals of a plurality of battery monitoring chips corresponding to the plurality of battery groups tend to be consistent.

2. The battery management system according to claim 1, characterized in that: The control unit reads the voltage information and time information of each battery monitoring chip respectively; and obtains the corresponding calculation signal according to the voltage information and time information of each battery monitoring chip respectively.

3. The battery management system according to claim 1, characterized in that: The maximum value of all the calculated signals is used as a reference value of the input current, and the compensation current is generated according to the difference between each of the calculated signals and the reference value of the input current.

4. The battery management system according to claim 1, characterized in that: The current compensation module is a current source built into the battery monitoring chip, and the current source is used to output the compensation current.

5. The battery management system according to claim 4, characterized in that: According to the difference between each of the calculation signals and the reference value of the input current, different step sizes are selected to adjust the corresponding current source to output the corresponding compensation current, wherein the value of the step size is positively correlated with the value of the corresponding difference.

6. The battery management system according to claim 1, characterized in that: At least some components of the DC-DC converter are built into the battery monitoring chip.

7. The battery monitoring chip according to claim 6, characterized in that: The voltage information is the input voltage and the output voltage of the DC-DC converter, and the time information is the switching cycle of the main power switch of the DC-DC converter and the conduction time in each switching cycle.

8. The battery management system according to claim 1, characterized in that: The DC-DC converter is a Buck converter and operates in DCM mode.

9. The battery management system according to claim 8, characterized in that: The calculation signal is directly proportional to the square of the on-time of the main power switch in each switching cycle and the difference between the input voltage and the output voltage of the DC-DC converter, and is inversely proportional to the switching cycle of the main power switch.

10. The battery management system according to claim 1, characterized in that: The DC-DC converter is a Buck-Boost converter and operates in a DCM mode.

11. The battery management system according to claim 10, characterized in that: The calculation signal is in direct proportion to the square of the on-time of the main power switch in each switching cycle and the input voltage of the DC-DC converter, and in inverse proportion to the switching cycle of the main power switch.

12. The battery management system according to claim 1, characterized in that: The control unit communicates with the multiple battery monitoring chips through a daisy chain to read the voltage information and time information of each battery monitoring chip and generate multiple calculation signals accordingly, and compensates the input current of each battery monitoring chip according to the multiple calculation signals until all the calculation signals are close to consistent.

13. A power consumption balancing method for balancing power consumption among a plurality of battery monitoring chips, each of the battery monitoring chips being used to monitor status information of a corresponding battery pack, the method comprising: generating a calculation signal representing an input current at an input end of the monitoring chip, the calculation signal being determined by a topology of the DC-DC converter, the DC-DC converter being used to receive a battery pack voltage at the input end of the monitoring chip and convert it into a supply voltage for supplying power to the monitoring chip; A compensation current is generated according to each of the calculation signals to compensate for the input current of each battery monitoring chip respectively so that the calculation signals of multiple battery monitoring chips tend to be consistent.

14. The power consumption balancing method according to claim 13, characterized in that: The compensation current is added to the input current to compensate for the input current.

15. The power consumption balancing method according to claim 13, characterized in that: The maximum value of the calculated signal is used as a reference value of the input current, and the compensation current is generated according to the difference between each of the calculated signals and the reference value of the input current.

16. The power consumption balancing method according to claim 13, characterized in that: The compensation current is outputted through a current source built into the battery monitoring chip.

17. The power consumption balancing method according to claim 16, characterized in that: According to the difference between each of the calculation signals and the reference value of the input current, different step sizes are selected to adjust the corresponding current source to output the corresponding compensation current, wherein the value of the step size is positively correlated with the value of the corresponding difference.

18. The power consumption balancing method according to claim 13, characterized in that: At least some components of the DC-DC converter are built into the battery monitoring chip.

19. The power consumption balancing method according to claim 13, characterized in that: The power consumption among multiple battery monitoring chips is balanced by balancing the input current of the DC-DC.

20. The power consumption balancing method according to claim 13, characterized in that: The voltage information is the input voltage and the output voltage of the DC-DC converter, and the time information is the switching cycle of the main power switch of the DC-DC converter and the conduction time in each switching cycle.

21. The power consumption balancing method according to claim 13, characterized in that: The DC-DC converter is a Buck converter and operates in DCM mode.

22. The power consumption balancing method according to claim 21, characterized in that: The calculation signal is directly proportional to the square of the on-time of the main power switch in each switching cycle and the difference between the input voltage and the output voltage of the DC-DC converter, and is inversely proportional to the switching cycle of the main power switch.

23. The power consumption balancing method according to claim 13, characterized in that: The DC-DC converter is a Buck-Boost converter and operates in a DCM mode.

24. The power consumption balancing method according to claim 23, characterized in that: The calculation signal is in direct proportion to the square of the on-time of the main power switch in each switching cycle and the input voltage of the DC-DC converter, and in inverse proportion to the switching cycle of the main power switch.

25. The power consumption balancing method according to claim 13, characterized in that: The control unit communicates with the multiple battery monitoring chips through a daisy chain to read the voltage information and time information of each battery monitoring chip and generate multiple calculation signals accordingly, and compensates the input current of each battery monitoring chip according to the multiple calculation signals until all the calculation signals are close to consistent.

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